However, the server operation process is abysmal. We have had to reboot the server 3 times in the middle of the morning every 48 hours since the upgrade. The symptom is that the web server becomes too slow for users to login, or do anything meaningful in webmail. The CPU grows to 100-140%. It is fixed by a server reboot, but it comes back every 48 hours or so.

However, the server operation process is abysmal. We have had to reboot the server 3 times in the middle of the morning every 48 hours since the upgrade. The symptom is that the web server becomes too slow for users to login, or do anything meaningful in webmail. The CPU grows to 100-140%. It is fixed by a server reboot, but it comes back every 48 hours or so.

The solution is "don't upgrade"!! Seems 8.8 was an "in hurry" release - Zimbra was used to be somekind of a "stable" product - this is going away the door also - not only the support (being miserable and irresponsive)